Blackboard-eraser.



No. 949,599. Patented May 15 1990. G. F. DEFORREST. BLACKBOARD EBASER. Alication filed Dec. 19

(No Modai.)

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' STATES GEORGE F. DE FORREST, OF IIUNTINGDON, PENNSYLVANIA.

BLACKBOARD-ERASER.

SPECIFICATION forming part of Letters Patent No. 649,599, dated May 15,1900.

Application filed December 19, 1898. Serial No. 699,731. (No model.)

To aZZ whom it may concern:

Beit known that I, GEORGE F. DE FORREST, a citizen of the UnitedStates,residing at Hunt ingdon, in the county of Huntingdon and State ofPennsylvania, have invented a new and useful Blackboard-Eraser, of whichthe following is a specification.

My invention relates to improvements in blackboard-erasers; and theobjects in view are to provide an improved device which is composedentirely of fabric for the purpose of making the device practicallynoiseless when it falls upon the floor, to secure a double workingsurface to the implement, which enables it to be used reversibly, andthereby prolongs the life and service thereof, and which provides asecure hand-grasp.

My eraser, being made entirely of fabric, will not make enough noisewhen it falls on the floor to annoy the teachers or pupils in theschool-rooms, and if theimplement is used as a missile by an angry orunruly pupil it will not injure the person whom it may strike even ifthrown with considerable force. The parts of the eraser are bound orunited firmly together to present a solid compact structure, and thefibrous eraser-body, while it serves as an efficient surface foreffacing crayonmarks, will not absorb the particles of crayon to such anextent as to render it difficult to cleanse the device.

lVith these ends in View my invention consists in the construction andarrangement of parts which will be hereinafter fully described andclaimed.

To enable others to understand the invention, I have illustrated thesame in the accompanying drawings, forming a part of the specification,and in which Figure l is a perspective view of an eraser constructed inaccordance with the invention. Fig. 2 is a vertical longitudinalsectional view thereof. Fig. 3 is a vertical cross-section. Fig. 4 is ahorizontal sectional view taken longitudinally through anotherembodiment of the invention. Fig. 5 is a vertical cross-section throughan eraser constructed as represented by Fig. 4.

Like numerals of reference denote like and corresponding parts in eachof the several figures of the drawings.

The'eraser of my invention is designated in its entirety by the numeral10, and, as represented by the drawings, it is substantially oblong inform with rounded blunt ends 11. This eraser is constructed entirely offabric, as will hereinafter appear, to provide working surfaces 12 13 onthe opposite faces of the body, and the implement is furthermoreconstructed to give the sides thereof a peculiar cross-sectional contourwhich enables the operator to grasp the implement very firmly in eitherof the positions of use of the device. The eraser is reversible side forside to bring either of its working faces 12 13 in contact withablackboard or other surface from which it is desired to elface crayonor chalk marks, and by making the implement with two worle ing surfacesand constructing its body so that it may be grasped in either adjustmentthe life and service of the device are materially prolonged and it iswell adapted for use by the operator.

The eraser consists of a fibrous core 14, a coiled or wrapped fabricbody 15, and a case or sheath 16, which is flush with the coiled body topresent both of the working surfaces of the implement to view. The core14 may consist of a single continuous piece of felt or other analogousmaterial of the proper shape and dimensions, around which the strip orlength of fabric is wrapped compactly to produce the coiled body 15; butI do not limit myself to the particular type of core shown by Figs. 1 to3, inclusive, because this core may consist of a coiled piece of fabric,as represented by Figs. 4 and 5. The core 17 in the embodiment of theinvention shown by Figs. 4C and 5 is made or composed of a single pieceof fabric wrapped upon itself until it attains the desired thickness andcontour in longitudinal and transverse section, and around this core 17is wrapped the fabric which produces the coiled body 15. When the coiledfabric core 17 is employed, I make the core of a number of layers ofrelativelystiff fabric, which are united firmly together to present acomparatively-stiff piece of fabric, and the laminations or layers ofthe fabric are joined by a suitable cementitious substance, such as glueor paste.

In the manufacture of my fabric b1ack board-eraser the core 14 or 17 isfirst produced, either by cutting the core from a single piece of feltor by wrapping a piece of fabric upon itself and uniting the laminationsby an adhesive substance. The fabric from which the coiled body 15 is tobe produced corresponds in width to the core, and the length of thefabric is such as to give the desired width to the implement. Thisfabric is of a soft nature as compared with the core, and the fabric iscoiled or wrapped the desired number of times around the core until thebody attains the desired width. The edges of the fabric forming thecoiled body are flush with the edges of the core, and the case or sheath16 is now applied for its edges to be flush with the core and the coiledbody. In applying the fabric around the core to produce the wrapped orcoiled body I may cement the laminations or layers of the fabric one tothe other in order to secure compactness and firmness; but the edges ofthe fabric body should not be cemented solidly together in order thatthe layers of the coiled body may yield or flex when the eraser isfrictionally brushed across the surface of a blackboard. After thesheath or casing has been wrapped one or more times around the coiledbody I subject the implement in its embryo condition to considerablepressure along the median line and on opposite sides in order to producetherein the longitudinal grooves 18 and to give the body across-sectional contour, which enables paratively free and yieldable.

it to be firmly grasped in the hand in either position of use of theimplement. It may be necessary to subject the fibrous implement toconsiderable pressure along its median line for the production of thegrooves 18 in the opposite faces of the tool, and by this step in theprocess of manufacturing the eraser the laminations or layers of thefabric are compacted solidly and rigidly along the central line of saideraser, thereby leaving the edges of the fabric forming the coiled bodycom- The compacted layers of the body along the central line of theeraser are prevented from expanding or returning to their normalcondition by means of transverse fasteners 19, which are insertedthrough the grooved pressed portions of the eraser. These fasteners mayconsist of rivets having separate plates or washers confined betweenheaded ends of the rivets and the compressed central part of theimplement, as shown by Figs. 4 and 5; but the form of the rivets is notmaterial, as fasteners headed at both ends may be used, as representedby Figs. 1 to 3, inclusive.

In my eraser the core and the fibrous web are essentially distinctelements one from the other; but they are so combined in a singlearticle as to contribute mutually to effacing the crayon and collectingthe dust. The core, while made of fibrous material, is essentiallynon-yieldable, so as to present a relativelyhard fibrous surface adaptedunder the greatest pressure that may be applied to the eraser not togive or be pressed away from the blackboard-surface, thus making thecore serve efficiently in effacing the chalk-marks. On the other hand,the coiled web is free or unconfined at both edges thereof, while themiddle part of the web is compressed along the line of the major axisthereof. This Web is thus arranged to leave relatively-small spacesbetween its laminations for the collection of the dust, and at the sametime the edges of the web are flush with the exposed edges of therelatively-hard core, so as to coact therewith in effacin g thechalk-marks. In the eraser using a one-piece core of Figs. 1 to 3,inclusive, a piece of compressed felt is employed, while in the eraserof Figs. 4 and 5 the core is pro duced by tightly winding a fabric stripand cementing the layers thereof together, so as to produce therelatively-hard non-yieldable fibrous core. The eraser of Figs. 4 and 5may thus be made economically of one kind of material. It is thereforeto be understood that my eraser has its elements confined to thoroughlyefiace the chalk-marks to the best advantage and to collect the loosedust.

The fabric used to form the case or sheath 16 is of a toughnon-absorbent nature, such as canvas or duck, in order to make thedevice wear to the best advantage and to pre vent absorption orsaturation by the crayon or chalk; but the particular material used forthe sheath is not important.

By making the eraser entirely of fabric it is practically noiseless inservice and will not annoy the occupants of a school-room when it dropson the floor. By pressing the fabric eraser along its median line theedges of the fabric body are left free or unconfined except as to theextent afforded by the case or sheath in order that the edges of thesoft fabric may serve as efficient erasive surfaces, and at the sametime the body is constructed with a solid central portion and is given across-sectional contour which enables the implement to be firmlygrasped, the sides of the body being deflected or flared outwardly fromthe compressed central portion. The body is prevented from getting outof shape by the fasteners applied to the compressed portion thereof. Theimplement is constructed to prevent the penetration of the crayon orchalk into the compacted core, and the eraser may be cleansed from theaccumulated chalk with facility. The device may be manufactured and soldat a 10W figure, and it is simple and durable in construction.

Although the sheath 16 of the body is of tough material, the layers orlaminations of fabric forming the coiled body prevent absorbent surfacesand edges adapted to take up and hold the chalk-dust and prevent it fromfloating in the air of the school-room. The laminations of the coiledbody are relatively free at their edges and said laminations, as well asthe core, to absorb the chalkdust; but as the body is compacted underpressure along its transverse median line the dust does not penetrateclear through the eraser, thus enabling the implement to be cleansedwith greater facility.

I am aware that prior to my invention a blackboard-eraser has beenprovided consisting of a plurality of flat layers arranged inoverlapping order for the edges of all the layers to lie flush with eachother, fabric bindings supplied to the faces of the outside layers, androws of stitches which pass through the bindings and the layers on linesadjacent to and parallel with the side and end edges of the layers andthe bindings. I am also aware that it is not new to make the body of ablack board-eraser entirely of fabric which is coiled upon itself and tocombine with such fabric a flexible packing which provides for theattachment of aspring-handle. I am also aware that a two-partblackboard-rubber has been provided with a narrow working face, which iscoiled around one member of the eraser and is adjustable therewith inrelation to the other member of the eraser for the purpose of projectingthe Working face more or less according to the wear thereon; but allthese prior constructions are hereby disclaimed. In my implement afibrous core is employed. A web of fibrous material is wrappedcontinuously around this core for its edges to lie flush with the edgesof the core to cooperate therewith in forming working surfaces onopposite faces of the eraser, and the core and wrapped web are united byrivets, which are disposed centrally with relation to the article andwhich tend to compact the web, so as to closely draw the layers thereoftogether and around the fibrous core. This construction and arrangementof parts provides grooves in the opposite sides of the eraser for thepurpose of forming a convenient handhold in using either face of thearticle as the rubbing surface, and a further advantage resides in thefact that the edges of the coiled web are left free or unconfined, so asto yield or flex in the operation of the device for the purpose offorming a oomparatively-soft rubbing surface and of leaving spacesbetween the individual layers,which spaces collect the crayon in theoperation of the device.

Having thus described the invention, what I claim is 1. Ablackboard-eraser comprising a relatively-hard, non-yieldable fibrouscore, a fibrous web coiled continuously around the core and having bothedges flush therewith, forming the duplicate working faces one on eachside of the eraser, and fasteners passing through the core and the webin the plane of the longitudinal center of the eraser and compressingthe middle portion of the web and core tightly together, the edges ofthe Web being unconfined and free to flex or yield laterally on bothsurfaces of the eraser, substantially as and for the purposes described.

2. The blackboard-eraser herein shown and described comprising anelongated relativelyhard, non-yieldable fibrous core having lay erscoiled upon themselves, a relativelysoft absorbent fibrous web coiled orwrapped con tinuously around the sides and ends of the fibrous core andhaving both edges thereof flush with the edges of the layers of saidcore, forming duplicate working faces one on each side of the eraser, awrapper of non-absorbent fabric inclosing the web, and transversefasteners lying in the same plane and passing through the middle portionof the eraser, said fasteners compressing the Web tightly at thelongitudinal center of the body and the edges of the web being free toflex or play laterally on both working surfaces of the eraser,substantially as described.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

GEO. F. DE FORREST.

Witnesses:

JAMES G. SPANGLER, L. E. EDWARDS.

